1. Technical Field
The present invention relates to a micropump having a tube unit and a control unit attachable to and detachable from each other.
2. Related Art
A wriggling pump is known as a device for transporting liquid at low speed. Recently, such a wriggling pump which rotates a rotor having a plurality of rollers by a step motor as a driving source has been proposed. According to this pump, the rotor rotates along a flexible tube while revolving the plural rollers to suck and deliver liquid (for example, see Japanese Patent No. 3177742).
This type of pump includes a pump module having a tube and a rotor for closing the tube with pressure, and a motor module having a step motor and an output gear mechanism stacked on each other. The pump further includes a gear as a connection element disposed on a rotation shaft of the rotor, and a pinion as a power extracting mechanism disposed on the output gear mechanism. When the pump module and the motor module are stacked for connection, the pinion and the gear engage with each other (tooth engagement) such that rotational driving force of the step motor can be transmitted to the rotor.
According to the structure shown in Japanese Patent No. 3177742, the motor module containing the step motor as the driving source, the output gear mechanism, and the control circuit, and the pump module containing the rotor which includes the tube and the rollers and the connection element are stacked on each other. Thus, the thickness of the structure is difficult to be reduced.
Moreover, a part of the tube is closed with pressure by the rollers for the period from manufacture (assembly) of the pump module to start of use. Thus, restoration ability of the tube lowers, and delivery accuracy decreases.
Furthermore, in the structure which stacks the pump module and the motor module on each other for connection to transmit the rotational driving force of the step motor to the rotor by tooth engagement between the pinion and the gear as the connection elements, the connecting and coupling structure becomes complicated, and assembly becomes difficult.